How to Install a Toilet Flange

How to Install a Toilet Flange Correctly

Learning how to install a toilet flange starts with the right fitting, a sound floor and the correct height. This guide covers the tools, preparation and steps for a typical floor-mounted toilet. It also explains when to call a plumber.

The flange joins the toilet to the drain and holds its mounting bolts. Together with the seal, it helps prevent wastewater leaks and sewer gas. However, the work depends on the pipe, floor and toilet model.

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Check the Cause Before Replacing Parts

A loose toilet, damp floor or broken bolt slot may point to flange damage. However, water can also come from the supply hose or tank. Find the source before buying parts. If water is spreading, stop using the toilet and arrange urgent plumbing help.

Tools for Toilet Flange Installation

First, check the fitting and toilet manuals. Your tools and materials may include:

• A compatible flange, new closet bolts and a new wax ring or approved wax-free seal.
• An adjustable wrench, screwdriver, tape measure and level.
• A putty knife, bucket, sponge, towels and floor protection.
• Gloves, eye protection and a suitable removable drain plug.
• A drill and fasteners suited to the floor.
• Pipe tools, cement and primer where the chosen fitting requires them.

Also, arrange help to lift the toilet. Porcelain fixtures are heavy and can crack if handled roughly.

Choose the Right Toilet Flange Replacement

Check the pipe material, diameter and joint type. Some flanges fit inside a pipe; others fit over it. Therefore, do not choose one by appearance alone. It must also suit the existing drain and local requirements.

A repair ring may suit a broken mounting ring if the flange body and drain joint remain sound. However, a cracked body or leaking joint needs a different repair. Oatey’s repair guide explains these options.

When learning how to install a toilet flange, remember that cast-iron drains do not all use the same connection. For example, an old lead bend or damaged iron pipe needs careful assessment.

How to Install a Toilet Flange: Step by Step

These steps explain how to install a toilet flange during replacement. For new pipework or a different toilet design, follow the specific product instructions. Before changing drain lines, also check the City of Toronto’s plumbing permit guidance.

1. Shut Off the Water and Remove the Toilet

First, close the supply valve and flush. Then, sponge out the remaining water from the tank and bowl. If the valve does not stop the flow, resolve that problem before disconnecting anything.

Next, disconnect the supply line over a bucket. Next, remove the bolt caps, nuts and any caulk holding the base. Gently release the old seal, then lift the toilet with help onto a padded surface. Avoid forcing or striking the porcelain.

2. Inspect the Floor and Drain

Scrape away the old wax from the flange and toilet outlet. Then, use a properly sized removable drain plug to keep debris and sewer gas out while the drain is open.

Next, check for cracks, loose screws and soft flooring. Repair damaged support before installing a toilet flange. This is because a new fitting cannot hold securely in a rotten subfloor. Also, identify the existing joint before attempting to remove the old flange.

3. Check Toilet Flange Installation Height

Measure the rough-in from the finished wall, excluding the baseboard, to the drain centre. Many toilets use a 12-inch rough-in, but check your model. Also, confirm the required clear space around the bowl.

For a typical new installation, the mounting ring rests on the finished floor. However, check the flange and seal instructions for the exact setup. If new tile leaves the flange too low, a compatible extension kit may help.

4. Connect the New Flange

Remove the old fitting using the method suited to its joint. However, if this risks damaging the drain, stop and call a plumber. For a new solvent-weld fitting, cut only to its specified depth. Then, clean and deburr the pipe and check the fit.

Use PVC cement for a compatible PVC joint and ABS cement for a compatible ABS joint. Use primer where required. In contrast, mechanical fittings have their own sealing method. Follow the label for ventilation, assembly and cure time, and align the bolt positions before the joint sets.

5. Anchor the Mounting Ring

Next, fasten the ring to sound support using the specified holes. For example, use suitable wood screws or concrete anchors for the floor type. Tile alone is not a firm fixing point. Also, check for hidden services before drilling.

The flange should stay still when secured. For more detail, see Oatey’s guidance on fitting height and anchoring.

6. Fit the Seal and Reset the Toilet

First, dry-fit the bowl before adding wax. It must rest securely on the floor without rocking. Therefore, fix height problems now; do not use the bolts to pull the bowl down.

Fit the new closet bolts and remove the temporary drain plug. Then, place the new wax ring or compatible wax-free seal as its instructions direct. Do this before lowering the bowl.

Next, lower the toilet straight over the bolts and press it down evenly. Once seated on wax, avoid lifting or rocking it. If you lift it again, replace the compressed wax ring.

Next, fit the washers and nuts. Tighten each side a little at a time. However, stop before excess force cracks the bowl. The bolts hold the toilet in place; they should not force it against a flange that sits too high.

7. Reconnect and Test for Leaks

Reconnect the supply as its instructions direct, then open the valve slowly. Also, check the hose and tank joints. Next, flush several times and check around the base. If you find a leak, stop using the toilet and correct the cause.

Finish the base seal as the toilet manual and local requirements direct. However, caulk cannot fix a leaking waste seal. Finally, recheck the floor and connections after use.

When to Call a Plumber

Knowing how to install a toilet flange includes spotting work beyond a simple replacement. Get help with damaged drains, old lead joints, soft floors or repeat leaks. A plumber can then explain the repair scope before work starts. Our guide on when to get professional help covers other warning signs.

Need Help with a Loose or Leaking Toilet?

Call GTA Restoration to discuss toilet repairs, flange damage and water leaks.

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Learn More

When to Call a Plumber | Common Plumbing Problems | Ways to Avoid Plumbing Emergencies